CN111983034B - Method for Calibrating Oil Film Stiffness of Hydrostatic Guideway Based on Ultrasonic Technology - Google Patents

Abstract

A method for calibrating oil film rigidity of a hydrostatic guideway based on an ultrasonic technology belongs to the technical field of oil film rigidity calibration. The method comprises the following steps: driving the hydrostatic guideway to reach a measuring position, adhering a water tank to the hydrostatic guideway, and adding water; immersing the head of the ultrasonic transducer in water, starting an ultrasonic signal generating and receiving module, setting ultrasonic parameters, and calculating the thickness of an oil film; applying a load on the upper slide carriage, and measuring the thickness value of the oil film after each loading by utilizing an ultrasonic detection device; each time the load value is changed, returning to the previous step, and executing the next step after the oil film thickness under all loads is measured; recording each load value and the oil film thickness value thereof in a test data recording table; calculating the oil film rigidity; and taking the load value as a Y coordinate and the oil film thickness value as an X coordinate, and adopting a linear least square method to linearly fit the load value and the oil film thickness value, wherein the absolute value of the slope of the obtained fitting straight line is the oil film rigidity. The method is used for calibrating the oil film rigidity of the hydrostatic guideway.

Description

Method for calibrating oil film stiffness of hydrostatic guideway based on ultrasonic technology

Technical Field

The invention belongs to the technical field of oil film stiffness calibration, and in particular relates to a method for calibrating the oil film stiffness of a liquid hydrostatic guide rail based on ultrasonic technology.

Background Art

Hydrostatic guides are important components of ultra-precision machine tools. The dynamic characteristics of hydrostatic guides directly affect the machining accuracy and machining level of ultra-precision machine tools. The oil film stiffness of hydrostatic guides is an indicator for evaluating the load-bearing capacity and motion stability of hydrostatic guides.

At present, when measuring the stiffness of the oil film, a fixed weight or a pressure cylinder is used to apply a vertical load to the slide of the liquid hydrostatic guide rail, and a displacement sensor is used to measure the displacement of the upper slide when the load is applied. The displacement of the upper slide is used to approximately replace the deformation of the oil film. The comparison relationship between the load force and the displacement is obtained based on multiple measurement results, so as to determine the load value that the oil film can withstand per unit deformation, that is, the stiffness of the oil film. However, this method will cause a certain deformation of the slide on the guide rail when applying the load, whether it is a fixed weight or a pressure cylinder. Therefore, the displacement deformation obtained by the measuring sensor includes both the static deformation of the slide on the guide rail and the deformation of the oil film thickness. Therefore, when the displacement of the slide on the guide rail is used to approximately replace the deformation of the oil film for calculation, the final obtained oil film stiffness will have a certain deviation from the actual value, thereby affecting the accuracy of the oil film stiffness measurement.

Summary of the invention

The purpose of the present invention is to provide a method for calibrating the oil film stiffness of a liquid hydrostatic guide rail based on ultrasonic technology. The method can perform non-destructive measurement of oil films with a thickness of micrometer level, effectively improve the measurement accuracy of the oil film stiffness, and is suitable for measuring and calibrating the oil film stiffness of a liquid hydrostatic guide rail.

Accurately calibrating the oil film thickness is an important basis for obtaining the oil film stiffness. Therefore, the present invention proposes a method for calibrating the oil film stiffness of a liquid hydrostatic guide rail based on ultrasonic technology, and adopts an ultrasonic nondestructive testing method to perform nondestructive testing on the oil film thickness, thereby improving the measurement accuracy of the oil film stiffness. The ultrasonic measurement method of the oil film stiffness of a liquid hydrostatic guide rail can overcome the shortcomings of the previous methods. Through the ultrasonic nondestructive testing technology, the oil film thickness and its deformation can be accurately measured, thereby obtaining the true oil film stiffness.

In order to solve the above technical problems, the technical solution adopted by the present invention is:

A method for calibrating the oil film stiffness of a liquid hydrostatic guide rail based on ultrasonic technology, the method is implemented by using an ultrasonic detection device for measuring the thickness of the oil film of a liquid hydrostatic guide rail, the ultrasonic detection device for measuring the thickness of the oil film of a liquid hydrostatic guide rail comprises a gantry, a horizontal moving platform, a vertical moving platform, a two-dimensional angle adjustment platform, an ultrasonic transducer, and an ultrasonic signal generating and receiving module; the ultrasonic transducer is fixedly connected to the two-dimensional angle adjustment platform through a transducer bracket, the two-dimensional angle adjustment platform is fixedly mounted on the vertical moving platform, the vertical moving platform is fixedly mounted on the horizontal moving platform, the horizontal moving platform is fixed on the horizontal beam of the gantry, and the gantry is fixedly mounted on the horizontal beam of the gantry. The gantry is fixed on the bed of the ultra-precision machining machine tool, and the ultrasonic signal generating and receiving module is fixed on the bed of the ultra-precision machining machine tool; the ultrasonic signal generating and receiving module and the ultrasonic transducer are bidirectionally connected through cables for signal transmission; the two-dimensional angle adjustment platform is formed by superposition of a pitch platform and a yaw platform, the pitch platform is located at the lower part of the yaw platform, the pitch platform and the yaw platform have the same structure, the pitch platform includes a pitch adjustment knob, a pitch platform locking screw, a pitch platform fixing component, a pitch platform locking plate, a pitch platform rotating component and a pitch platform worm; the yaw platform includes a yaw adjustment knob, a yaw platform locking screw, a yaw platform fixing component, a yaw platform locking plate, a yaw platform rotating component and a yaw platform worm;

The yaw table rotating component, the yaw table fixing component, the pitch table rotating component and the pitch table fixing component are stacked in sequence from top to bottom, the yaw table fixing component and the pitch table rotating component are detachably fixedly connected, the upper surface of the pitch table fixing component is provided with an inner groove that runs through the front and rear side walls, the middle parts of the left and right side walls of the inner groove are provided with a protrusion that protrudes upward, the two top angles of the upper surface of the protrusion are respectively a right angle and an inverted V-shaped angle, the protrusions located on the left and right side walls of the inner groove are symmetrically arranged relative to the center of the pitch table fixing component, the lower surface of the pitch table rotating component is provided with an arc-shaped protrusion, and the left and right sides of the pitch table rotating component are respectively provided with protrusions that are symmetrical with the The projection is matched with a guide groove, the pitch adjustment knob is fixedly connected to one end of the pitch platform worm, the left and right side walls of the pitch platform fixing component are coaxially provided with two through holes, the two ends of the pitch platform worm are rotatably connected with the two through holes, the arc-shaped protrusion of the pitch platform rotating component is made into a worm gear structure meshing with the pitch platform worm, a threaded hole is provided on the front side wall or the rear side wall of the pitch platform rotating component, the pitch platform locking piece is arranged at the front side wall or the rear side wall of the pitch platform rotating component and the pitch platform fixing component, the pitch platform locking piece is provided with a circular arc long groove, the pitch platform locking screw penetrates into the circular arc long groove and is threadedly connected with the threaded hole;

The upper surface of the deflection platform fixing component is provided with two inner grooves that pass through the left and right side walls, and the middle parts of the front and rear side walls of the inner groove are each provided with two upwardly protruding protrusions, and the two top angles on the upper surface of the two protrusions are respectively a right angle and an inverted V-shaped angle, and the two protrusions located on the front and rear side walls of the inner groove are symmetrically arranged relative to the center of the deflection platform fixing component, and the lower surface of the deflection platform rotating component is provided with two arc-shaped protrusions, and the front and rear sides of the deflection platform rotating component are respectively provided with two guide grooves that match the two protrusions, the deflection adjustment knob is fixedly connected to one end of the deflection platform worm, and the front and rear side walls of the deflection platform fixing component are coaxially provided with two through holes Second, the two ends of the sway table worm are rotatably connected with the two through holes; the arc-shaped protrusion of the sway table rotating component is made into a worm gear structure meshing with the sway table worm; a threaded hole is provided on the left side wall or the right side wall of the sway table rotating component; the sway table locking plate is arranged on the left side wall or the right side wall of the sway table rotating component and the sway table fixed component; the sway table locking plate is provided with an arc-shaped long groove; the sway table locking screw penetrates into the arc-shaped long groove and is threadedly connected with the threaded hole; the ultrasonic transducer is fixedly connected to the sway table rotating component through the transducer bracket; the method steps are as follows:

Step 1: driving the hydrostatic guide rail to reach the measuring position;

Step 2: Glue the water tank to the upper end of the hydrostatic guide rail just above the oil film to be tested, and add tap water or purified water into the water tank;

Step 3: Drive the horizontal moving platform to adjust the lateral position of the ultrasonic transducer so that the ultrasonic transducer is directly above the water tank; drive the vertical moving platform to adjust the height position of the ultrasonic transducer so that the head of the ultrasonic transducer is gradually immersed in the water in the water tank, ensuring that the head of the ultrasonic transducer maintains a distance of 2-10mm from the upper slide surface of the hydrostatic guide rail;

Step 4: adjusting the pitch and yaw angles of the two-dimensional angle adjustment platform so that the axis of the ultrasonic transducer is perpendicular to the surface of the upper slide;

Step 5: Start the ultrasonic signal generating and receiving module, which includes an ultrasonic signal generating module and an ultrasonic signal receiving module. Set the ultrasonic parameters in the ultrasonic signal generating module, i.e., the intensity and frequency of the ultrasonic wave. The formula for calculating the oil film thickness is as follows;

Where: h is the oil film thickness;

c is the propagation speed of ultrasonic wave in oil film;

m is the resonance order of the oil film;

f _m is the m-th order resonance frequency of the oil film;

Step 6: Apply a load to the upper slide of the hydrostatic guide rail through a cylinder, the load increases by 500N, and is gradually loaded to 2500N, and the ultrasonic detection device is used to measure the oil film thickness value after each loading; in this step, each time the load value is changed, it is necessary to return to step 5 and re-measure the oil film thickness to determine the corresponding oil film thickness when the load is applied, and after the oil film thickness under all loads is measured, step 7 is executed;

Step 7: Record each load value and its corresponding oil film thickness value in the test data record table;

Step 8: As the load acting on the oil film continues to increase, the thickness of the oil film will gradually become thinner. Calculate the ratio of each load change to the change in oil film thickness, i.e. the oil film stiffness;

Where: k is the oil film stiffness, in N/μm, representing the load value that the oil film can withstand per unit deformation;

ΔF is the load change, the load increases by 500N and gradually loads to 2500N;

Δh is the change in oil film thickness after each loading;

Since the load change ΔF is a fixed value, and the oil film thickness change Δh after each loading is constantly changing, there is a difference in the oil film stiffness value between any two adjacent measurement points, and the oil film stiffness value cannot be accurately obtained. Therefore, the load value is used as the Y coordinate and the oil film thickness value is used as the X coordinate. The linear least squares method is used to perform linear fitting on the load value and the oil film thickness value. The absolute value of the slope of the fitted straight line is the oil film stiffness.

The beneficial effects of the present invention relative to the prior art are:

The present invention uses ultrasonic technology to calibrate and measure the oil film stiffness of the liquid hydrostatic guide. The measurement method proposed by the present invention can realize non-destructive measurement of the oil film thickness, avoiding the measurement error caused by the deformation of the upper slide plate and approximate estimation of the liquid hydrostatic guide in other indirect measurement methods. The oil film thickness is measured according to the reflection and transmission principle of ultrasonic waves, and the oil film thickness can be accurately measured by collecting the reflection signal of the interface on both sides of the oil film. The present invention uses the linear least squares method to linearly fit the load value and the oil film thickness value, and then obtains the oil film stiffness of the liquid hydrostatic guide, which can improve the measurement accuracy of the oil film stiffness.

Ultrasonic detection technology is one of the most widely used non-destructive testing technologies at present. The measurement method proposed in the present invention has the advantages of strong penetration ability, high measurement accuracy, high sensitivity, and friendly detection environment. In addition, the present invention has the characteristics of simple process operation, convenient data processing, and accurate results.

BRIEF DESCRIPTION OF THE DRAWINGS

1 is a schematic cross-sectional view of an ultrasonic wave propagation medium when measuring the oil film thickness using an ultrasonic detection device for measuring the oil film thickness of a liquid hydrostatic guide rail according to the present invention;

FIG2 is a schematic diagram of the ultrasonic reflection and transmission principle;

3 is a schematic structural diagram of an ultrasonic detection device for measuring the oil film thickness of a liquid hydrostatic guide rail according to the present invention;

FIG4 is a schematic diagram of the structure of a hydrostatic guide rail;

FIG5 is a schematic diagram of a cross-section of a hydrostatic guide rail, in which arrows indicate loading loads;

FIG6 is a schematic diagram of the ultrasonic wave generation and reception process;

FIG7 is a schematic structural diagram of a two-dimensional angle adjustment platform;

FIG8 is a cross-sectional view of a two-dimensional angle adjustment stage;

FIG9 is a schematic diagram of the structure of a horizontal moving platform;

FIG10 is a schematic structural diagram of a vertical mobile platform;

FIG11 is a partial enlarged view of point D in FIG3 ;

FIG12 is a partial enlarged view of point E in FIG9 ;

FIG. 13 is a partial enlarged view of point C in FIG. 10 .

The names and numbers of the components involved in the above drawings are as follows:

Ultrasonic transducer 1, transducer bracket 2, two-dimensional angle adjustment table 3, yaw adjustment knob 3-1, yaw table locking screw 3-2, pitch adjustment knob 3-3, pitch table locking screw 3-4, pitch table fixing component 3-5, pitch table locking plate 3-5-1, pitch table rotating component 3-6, yaw table fixing component 3-7, yaw table locking plate 3-7-1, yaw table rotating component 3-8, pitch table worm 3-9, vertical moving platform 4, locking device 4-1, fixing sleeve 4-1-1, handle 4-1-2, driving handle 4-2, vertical moving lead screw 4-3, gear protection cover 4-4, driving gear 4-5, driven gear 4-6, vertical moving guide rail slide 4-7, vertical Movable slider 4-8, bearing 4-9, support plate 4-10, vertical movable stage 4-11, vertical base 4-12, horizontal movable platform 5, horizontal movable lead screw 5-1, lead screw bearing seat 5-3, coupling 5-4, servo motor 5-5, horizontal movable stage 5-6, horizontal movable guide rail slide 5-7, lead screw horizontal movable slider 5-8, base one 5-9, gantry 6, bottom support 6-1, ultra-precision machining machine bed 7, liquid hydrostatic guide rail 8, base two 8-1, upper slide 8-2, side slide 8-3, lower slide 8-4, water tank 9, ultrasonic signal generating and receiving module 10, oil film 11, water 12, interface one 13, interface two 14, interface three 15.

DETAILED DESCRIPTION

In the description of the present invention, it is necessary to understand that “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside and outside”, “surface” and other indications of orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

Specific implementation method 1: As shown in FIG. 3, FIG. 6, and FIG. 11, this implementation method discloses a method for calibrating the oil film stiffness of a liquid hydrostatic guide rail based on ultrasonic technology, wherein the method is implemented by using an ultrasonic detection device for measuring the oil film thickness of a liquid hydrostatic guide rail, wherein the ultrasonic detection device for measuring the oil film thickness of a liquid hydrostatic guide rail comprises a gantry 6, a horizontal moving platform 5, a vertical moving platform 4, a two-dimensional angle adjustment platform 3, an ultrasonic transducer 1, and an ultrasonic signal generating and receiving module 10;

The ultrasonic transducer 1 is fixedly connected to the two-dimensional angle adjustment platform 3 through the transducer bracket 2, and the two-dimensional angle adjustment platform 3 is fixedly installed on the vertical movable platform 4 (through bolts) (the vertical movable platform 4 can drive the two-dimensional angle adjustment platform 3 and the ultrasonic transducer 1 to move in the vertical direction to adjust the height position of the ultrasonic transducer 1), and the vertical movable platform 4 is fixedly installed on the horizontal movable platform 5, and the horizontal movable platform 5 is fixed on the horizontal beam of the gantry 6 (the gantry 6 is connected to the ultra-precision machining machine bed 7 through the bottom support 6-1 and bolted, and the main function of the gantry 6 is to fix and support the horizontal movable platform 5 and to support the horizontal movable platform 5, a vertical moving platform 4 fixedly connected to the vertical moving platform 4, a two-dimensional angle adjustment platform 3 fixedly connected to the vertical moving platform 4, an ultrasonic transducer 1 fixedly connected to the two-dimensional angle adjustment platform 3 and other working parts), the gantry 6 is fixed on the ultra-precision machining bed 7, and the ultrasonic signal generating and receiving module 10 is fixed on the ultra-precision machining bed 7; the ultrasonic signal generating and receiving module 10 and the ultrasonic transducer 1 are bidirectionally connected through a cable for signal transmission (the ultrasonic signal generating and receiving module 10 releases an excitation signal to excite the ultrasonic transducer 1 to generate an ultrasonic wave, and at the same time receives the ultrasonic reflected wave received by the ultrasonic transducer 1 and performs data processing on it, so as to obtain the measurement value of the thickness of the oil film 11);

The method steps are as follows:

Step 1: driving the hydrostatic guide rail 8 to reach the measuring position;

Step 2: Glue the water tank 9 (without the bottom plate) to the upper end of the liquid hydrostatic guide rail 8 just above the oil film 11 to be tested (make sure that there is no water leakage at the bonding point between the water tank 9 and the liquid hydrostatic guide rail 8, and add tap water or purified water to the water tank 9;

Step 3: drive the horizontal moving platform 5 to adjust the lateral position of the ultrasonic transducer 1 so that the ultrasonic transducer 1 is directly above the water tank 9; drive the vertical moving platform 4 to adjust the height position of the ultrasonic transducer 1 so that the head of the ultrasonic transducer 1 is gradually immersed in the water in the water tank 9, ensuring that the head of the ultrasonic transducer 1 maintains a distance of 2-10mm from the upper surface of the upper slide plate 8-2 of the liquid hydrostatic guide rail 8;

Step 4: Adjust the pitch and yaw angles of the two-dimensional angle adjustment platform 3 (to achieve the spatial posture of the ultrasonic transducer 1) so that the axis of the ultrasonic transducer 1 is perpendicular to the surface of the upper slide plate 8-2 (to obtain a higher ultrasonic reflectivity);

Step 5: Start the ultrasonic signal generating and receiving module 10. The ultrasonic signal generating and receiving module 10 includes an ultrasonic signal generating module and an ultrasonic signal receiving module. The ultrasonic parameters, i.e., the intensity and frequency of the ultrasonic wave, are set in the ultrasonic signal generating module (the present invention is based on the ultrasonic reflection method for measurement, and the intensity of the ultrasonic wave is one of the important factors affecting the final reflectivity. Therefore, it is necessary to set the intensity of the ultrasonic wave in the ultrasonic signal generating module. Regarding the frequency, the frequency is not set to a fixed value here, but the frequency of the ultrasonic wave is adjusted from low to high. When the thickness of the oil film is constant, its corresponding resonant frequency _fm is a constant value. In the process of increasing the frequency of the ultrasonic wave from low to high, when the frequency of the ultrasonic wave is equal to the resonant frequency _fm of the oil film, the oil film resonates. At this time, the reflectivity of the ultrasonic wave received by the ultrasonic signal receiving module is zero. Therefore, the resonant frequency _fm of the oil film can be determined according to the frequency of the ultrasonic wave in the ultrasonic signal generating module, and the thickness of the oil film can be further calculated according to the formula. Usually, m is 1, and the calculation is performed based on the first-order resonant frequency of the oil film 11). The formula for calculating the thickness of the oil film is as follows;

Where: h is the oil film thickness;

c is the propagation speed of ultrasonic waves in the oil film 11 (this value is related to the properties of the oil itself);

m is the resonance order of the oil film 11;

f _m is the m-th order resonance frequency of the oil film 11;

Step 6: Apply a load to the upper slide 8-2 of the hydrostatic guide rail 8 through a cylinder, the load is increased by 500N, and gradually loaded to 2500N, and the ultrasonic detection device is used to measure the oil film thickness value after each loading; in this step, each time the load value is changed, it is necessary to return to step 5 and re-measure the oil film thickness to determine the corresponding oil film thickness when the load is applied. After the oil film thickness under all loads is measured, step 7 is executed;

Step 7: Record each load value and its corresponding oil film thickness value in the test data record table;

Step 8: As the load acting on the oil film 11 continues to increase, the thickness of the oil film will gradually become thinner, and the ratio of each load change to the oil film thickness change, i.e., the oil film stiffness, is calculated;

Where: k is the oil film stiffness, in N/μm, representing the load value that the oil film can withstand per unit deformation;

ΔF is the load change, the load increases by 500N and gradually loads to 2500N;

Δh is the change in oil film thickness after each loading;

Since the load change ΔF is a fixed value, and the oil film thickness change Δh after each loading is constantly changing, there is a difference in the oil film stiffness value between any two adjacent measurement points, and the oil film stiffness value cannot be accurately obtained. Therefore, the load value is used as the Y coordinate and the oil film thickness value is used as the X coordinate. The linear least squares method is used to perform linear fitting on the load value and the oil film thickness value. The absolute value of the slope of the fitted straight line is the oil film stiffness.

Ultrasonic transducer 1: It is both an ultrasonic wave emitting device and an ultrasonic wave receiving device, transmitting ultrasonic waves to the object to be detected (oil film 11) and collecting ultrasonic waves reflected from the object to be detected.

Ultrasonic signal generating and receiving module 10: The ultrasonic signal generating and receiving module 10 and the ultrasonic transducer 1 are connected via a cable for signal transmission. The ultrasonic signal generating and receiving module 10 releases an excitation signal to excite the ultrasonic transducer 1 to generate ultrasonic waves, and at the same time receives the ultrasonic reflected waves received by the ultrasonic transducer 1 and processes the data thereof, thereby obtaining the measurement value of the oil film thickness.

The two-dimensional angle adjustment platform 3 is used to adjust the pitch and yaw angles of the ultrasonic transducer 1, so as to achieve precise adjustment of the ultrasonic incident angle, so that the ultrasonic wave is incident on the surface of the oil film 11 as vertically as possible to obtain a higher reflectivity.

Vertical moving platform 4 : moves along the vertical direction with the two-dimensional angle adjustment platform 3 and the ultrasonic transducer 1 , so as to adjust the spatial vertical position of the ultrasonic transducer 1 .

The horizontal moving platform 5 moves the vertical moving platform 4 and the two-dimensional angle adjustment platform 3 and the ultrasonic transducer 1 thereon in the horizontal direction, so as to adjust the spatial horizontal position of the ultrasonic transducer 1 .

Gantry 6: It is mainly used to fix and support the horizontal moving platform 5 and other devices fixed to the horizontal moving platform 5, and is connected to the ultra-precision machining center bed 7 through the bottom support 6-1 and bolted.

Specific implementation method II: As shown in Figures 3, 7, 8 and 11, this implementation method is a further explanation of specific implementation method I. The two-dimensional angle adjustment platform 3 is composed of a pitch platform and a yaw platform superimposed on each other. The pitch platform is located at the lower part of the yaw platform. The pitch platform and the yaw platform have the same structure. The pitch platform includes a pitch adjustment knob 3-3, a pitch platform locking screw 3-4, a pitch platform fixing component 3-5, a pitch platform locking plate 3-5-1, a pitch platform rotating component 3-6 and a pitch platform worm 3-9; the yaw platform includes a yaw adjustment knob 3-1, a yaw platform locking screw 3-2, a yaw platform fixing component 3-7, a yaw platform locking plate 3-7-1, a yaw platform rotating component 3-8 and a yaw platform worm;

The tilt table rotating component 3-8, the tilt table fixing component 3-7, the pitch table rotating component 3-6 and the pitch table fixing component 3-5 are stacked in sequence from top to bottom, the tilt table fixing component 3-7 is detachably fixedly connected with the pitch table rotating component 3-6 (using bolts), the upper surface of the pitch table fixing component 3-5 is provided with an inner groove one that runs through the front and rear side walls (that is, a hollow structure is adopted to facilitate the installation of the pitch table worm 3-9), and the middle parts of the left and right side walls of the inner groove one are provided with a protruding block one that protrudes upward, and the two top angles of the upper surface of the protrusion one are respectively a right angle and an inverted V-shaped angle, The protrusions one on the left and right side walls of the inner groove one are symmetrically arranged relative to the center of the pitch platform fixed component 3-5, the lower surface of the pitch platform rotating component 3-6 is provided with an arc-shaped protrusion one, and the left and right sides of the pitch platform rotating component 3-6 are respectively provided with a guide groove one that matches the protrusion one, the pitch adjustment knob 3-3 is fixedly connected to one end of the pitch platform worm 3-9, the left and right side walls of the pitch platform fixed component 3-5 are coaxially provided with two through holes one, the two ends of the pitch platform worm 3-9 are rotatably connected to the two through holes one, and the arc-shaped protrusion one of the pitch platform rotating component 3-6 is made to be compatible with the pitch platform worm 3 -9 meshing with the worm gear structure (i.e., the lower surface of the arc-shaped protrusion is provided with a plurality of teeth meshing with the pitch platform worm 3-9. When the pitch adjustment knob 3-3 is rotated, the pitch platform worm 3-9 rotates accordingly, thereby driving the arc-shaped protrusion of the pitch platform rotating component 3-6 to rotate along the guide groove, so that the pitch platform rotating component 3-6 forms a pitch angle to achieve angle adjustment), a threaded hole is provided on the front side wall or the rear side wall of the pitch platform rotating component 3-6, and the pitch platform locking plate 3-5-1 is arranged on the front side wall of the pitch platform rotating component 3-6 and the pitch platform fixed component 3-5 Or at the rear side wall, a circular arc long groove one is provided on the pitch platform locking piece 3-5-1, and the pitch platform locking screw 3-4 penetrates into the circular arc long groove one and is threadedly connected with the threaded hole one (when the pitch angle adjustment meets the requirements, the two-dimensional angle adjustment platform 3 can be tightened by rotating the pitch platform locking screw 3-4 until the pitch platform locking screw 3-4 is in close contact with the pitch platform locking piece 3-5-1, and the pitch platform rotating part 3-6 and the pitch platform locking piece 3-5-1 are tightly connected through the thread preload and friction force, thereby realizing the tightening of the two-dimensional angle adjustment platform 3);

The upper surface of the deflection table fixing component 3-7 is provided with two inner grooves that pass through the left and right side walls (that is, a hollow structure is adopted to facilitate the installation of the deflection table worm), and the middle parts of the front and rear side walls of the inner grooves are provided with two upwardly protruding protrusions, and the two top angles on the upper surface of the protrusions are respectively a right angle and an inverted V-shaped angle, and the protrusions located on the front and rear side walls of the inner grooves are symmetrically arranged relative to the center of the deflection table fixing component 3-7, and the lower surface of the deflection table rotating component 3-8 is provided with two arc-shaped protrusions, and the front and rear sides of the deflection table rotating component 3-8 are respectively provided with There is a guide groove 2 that matches the protrusion 2, the deflection adjustment knob 3-1 is fixedly connected to one end of the deflection table worm, and the front and rear side walls of the deflection table fixed component 3-7 are coaxially provided with two through holes 2, and the two ends of the deflection table worm are rotatably connected with the two through holes 2, and the arc-shaped protrusion 2 of the deflection table rotating component 3-8 is made into a worm gear structure that meshes with the deflection table worm (that is, the lower surface of the arc-shaped protrusion 2 is provided with a plurality of teeth that mesh with the deflection table worm. When the deflection adjustment knob 3-1 is rotated, the deflection table worm 9 rotates accordingly, thereby driving The worm gear of the movable deflection table rotating component 3-8 rotates along the guide groove 2, so that the deflection table rotating component 3-8 forms a deflection angle to achieve angle adjustment). A threaded hole 2 is provided on the left wall or the right wall of the deflection table rotating component 3-8. The deflection table locking plate 3-7-1 is arranged on the left wall or the right wall of the deflection table rotating component 3-8 and the deflection table fixed component 3-7. A circular arc long groove 2 is provided on the deflection table locking plate 3-7-1. The deflection table locking screw 3-2 penetrates into the circular arc long groove 2 and is connected with the The threaded hole is threadedly connected (when the yaw angle adjustment meets the requirements, the two-dimensional angle adjustment platform 3 can be tightened by rotating the yaw platform locking screw 3-2 until the yaw platform locking screw 3-2 is in close contact with the yaw platform locking plate 3-7-1, and the thread preload and friction force form a tight connection between the yaw platform rotating component 3-8 and the yaw platform locking plate 3-7-1, thereby realizing the tightening of the two-dimensional angle adjustment platform 3); the ultrasonic transducer 1 is fixedly connected to the yaw platform rotating component 3-8 through the transducer bracket 2.

The working principle is: the ultrasonic transducer 1 is connected to the two-dimensional angle adjustment platform 3 through the transducer bracket 2. The two-dimensional angle adjustment platform 3 adopts the form of a worm gear. By manually turning the pitch adjustment knob 3-3 and the yaw adjustment knob 3-1, the pitch and yaw angles of the ultrasonic transducer 1 can be adjusted, thereby obtaining a higher ultrasonic reflectivity.

Specific implementation method three: As shown in Figures 3, 7 and 8, this implementation method is a further explanation of specific implementation method two. The arc radius of the arc-shaped long groove one is the same as the rotation radius of the pitch platform rotating component 3-6 (thereby ensuring that the pitch platform locking screw 3-4 is always in the arc-shaped long groove one), and the arc radius of the arc-shaped long groove two is the same as the rotation radius of the tilt platform rotating component 3-8 (thereby ensuring that the tilt platform locking screw 3-2 is always in the arc-shaped long groove two).

Specific embodiment 4: As shown in Figures 3, 10 and 13, this embodiment is a further description of the specific embodiment 1, and the vertical moving platform 4 includes a driving handle 4-2, a vertical moving screw 4-3, a gear protection cover 4-4, a driving gear 4-5, a driven gear 4-6, a vertical moving stage 4-11, a vertical base 4-12, two bearings 4-9, two vertical moving guide rails 4-7, four vertical moving sliders 4-8 and two support plates 4-10;

The driving handle 4-2 is connected with the driving gear 4-5 through a rotating shaft to realize synchronous movement. The driving gear 4-5 is meshed with the driven gear 4-6 and is installed together in the gear protection cover 4-4. The driven gear 4-6 is fixedly installed on the vertical moving screw 4-3. The two support plates 4-10 are arranged opposite to each other and are both fixed on the vertical base 4-12, and one of the support plates 4-10 is fixedly connected to one end of the gear protection cover 4-4. A bearing 4-9 is installed at each end of the vertical moving screw 4-3. The two bearings 4-9 are arranged on the two support plates 4-10 coaxially provided In the two axial holes, two vertical movable guide rails 4-7 are arranged in parallel on both sides of the vertical movable screw 4-3, and the two vertical movable guide rails 4-7 are fixed on the vertical base 4-12, and both ends of the two vertical movable guide rails 4-7 are fixedly connected to the two support plates 4-10, and a vertical movable screw nut is screwed on the vertical movable screw 4-3, and the vertical movable screw nut (through four screws) is fixed on the back side of the vertical movable stage 4-11, and the vertical movable stage 4-11 is slidably connected to the two vertical movable guide rails 4-7 through four vertical movable sliders 4-8.

The working principle is:

The driving handle 4-2 is connected to the driving gear 4-5 through a rotating shaft to achieve synchronous movement. Rotating the driving handle 4-2 can drive the driving gear 4-5 to rotate. The driving gear 4-5 and the driven gear 4-6 are meshed with each other, thereby driving the driven gear 4-6 and the vertical moving screw 4-3 to make a rotational movement. The rotation of the vertical moving screw 4-3 will cause the vertical moving screw nut to move. The vertical moving screw nut is fixedly connected to the back of the vertical moving stage 4-11. Four vertical moving sliders 4-8 that slide with the vertical moving guide rail 4-7 are fixedly installed at the four corners of the back of the vertical moving stage 4-11. The vertical moving screw nut can drive the vertical moving stage 4-11 to move linearly, thereby achieving the purpose of adjusting the position.

The vertical moving platform 4 can drive the two-dimensional angle adjustment platform 3 and the ultrasonic transducer 1 to move in the vertical direction to adjust the height position of the ultrasonic transducer 1. The vertical moving platform 4 is mainly used for fine adjustment and has a small moving range, so it is manually driven. The driving handle 4-2 is rotated to drive the driving gear 4-5 coaxial with it to rotate, and the driving gear 4-5 is meshed with the driven gear 4-6 fixedly mounted on the lead screw 4-3, thereby driving the driven gear 4-6 and the lead screw 4-3 to rotate synchronously, thereby realizing the vertical movement of the vertical moving stage 4-11.

Specific implementation mode five: As shown in Figures 3, 10 and 13, this implementation mode is a further explanation of specific implementation mode four, and the vertical movable platform 4 also includes a locking device 4-1; the locking device 4-1 includes a fixing sleeve 4-1-1 with an opening, a handle 4-1-2 and a fastening screw; one end of the handle 4-1-2 is made integral with the fastening screw, and two open ends of the fixing sleeve 4-1-1 are coaxially provided with two screw holes, the fixing sleeve 4-1-1 is mounted on the rotating shaft, and the fastening screw is threadedly connected to the two screw holes.

Specific embodiment six: As shown in Figures 3, 9 and 12, this embodiment is a further description of the specific embodiment one, and the horizontal moving platform 5 includes a servo motor 5-5, a coupling 5-4, a horizontal moving stage 5-6, a horizontal moving screw 5-1, a base 5-9, two screw bearing seats 5-3, two horizontal moving guide rails 5-7 and four screw horizontal moving sliders 5-8;

The base 5-9 is fixedly connected to the front surface of the horizontal beam of the gantry 6, the servo motor 5-5, two screw bearing seats 5-3 and two horizontal movable guide rails 5-7 are all fixed on the base 5-9, the servo motor 5-5 is transmission-connected to one end of the horizontal movable screw 5-1 through a coupling 5-4, both ends of the horizontal movable screw 5-1 are supported by two screw bearing seats 5-3, the horizontal movable screw 5-1 and the two horizontal movable guide rails 5-7 are all arranged parallel to the horizontal beam of the gantry 6, and the two horizontal movable guide rails 5-7 are located on both sides of the horizontal movable screw 5-1, a horizontal movable screw nut is screwed on the horizontal movable screw 5-1, the horizontal movable screw nut is fixedly connected to the back side of the horizontal movable stage 5-6, and the horizontal movable stage 5-6 is slidingly connected to the two horizontal movable guide rails 5-7 through four screw horizontal movable sliders 5-8.

Working principle: The servo motor 5-5 and the horizontal moving screw 5-1 are connected by a coupling 5-4. The rotation of the servo motor 5-5 can drive the horizontal moving screw 5-1 to make a rotary motion, and then drive the horizontal moving screw nut and the horizontal moving stage 5-6 to achieve linear motion. The main function of the horizontal moving platform 5 is to move the vertical moving platform 4 and the two-dimensional angle adjustment platform 3 and the ultrasonic transducer 1 thereon in the horizontal direction to adjust the horizontal position of the ultrasonic transducer 1.

The working principle of the present invention is as follows: as shown in Fig. 3-Fig. 5, before testing, the water tank 9 is first placed on the hydrostatic guide rail 8, the hydrostatic guide rail 8 is a bilaterally symmetrical structure and is driven by a linear motor, and the base 2 8-1 of the hydrostatic guide rail 8 is fastened (by screws) on the ultra-precision machining machine bed 7 to form a fixed part of the hydrostatic guide rail, which is fixed together with the linear motor stator. The moving part of the hydrostatic guide rail 8 (including the upper slide 8-2, two side slides 8-3 and two lower slides 8-4) is fixed together with the linear motor mover and can move with it.

As shown in FIG4 , the hydrostatic guide rail 8 (the prior art) comprises an upper slide 8-2, a base 8-1, two lower slides 8-4 and two side slides 8-3; a side slide 8-3 is provided on the left and right sides of the lower end of the upper slide 8-2, a lower slide 8-4 is provided on the lower ends of the two side slides 8-3, the base 8-1 is provided on the two lower slides 8-4 and is located in the space surrounded by the upper slide 8-2 and the two side slides 8-3, and the side slides 8-3 are fastened and connected with the upper slide 8-2 and the lower slides 8-4 by screws to form a closed form corresponding to the base 8-1, as shown in FIG4 . An oil film 11 is provided between the upper slide 8-2 and the base 8-1, between the base 8-1 and the two lower slides 8-4, and between the two side slides 8-3 and the base 8-1. The upper slide 8-2, the side slide 8-3 and the lower slide 8-4 are provided with pre-processed throttling holes inside, which serve as flow channels for high-pressure lubricating oil. Under the action of high pressure, the lubricating oil forms an oil film 11 between the working surface of the base 8-1 and the working surfaces of the upper slide 8-2, the side slide 8-3 and the lower slide 8-4, as shown in FIG5 .

As shown in FIG5 , a concentrated load is applied to the upper slide plate 8 - 2 of the hydrostatic guide rail 8 by a cylinder, and the load is increased by 500 N and gradually loaded to 2500 N.

FIG6 is a schematic diagram of the ultrasonic wave generation and reception process. The ultrasonic wave signal generation and reception module 10 and the ultrasonic transducer 1 are connected by a cable for data transmission. The ultrasonic wave signal generation module of the ultrasonic wave signal generation and reception module 10 generates a high-frequency excitation signal, and excites the ultrasonic transducer 1 through the inverse piezoelectric effect, so that the chip assembly inside the ultrasonic transducer 1 generates mechanical vibration, thereby forming an ultrasonic wave. The thickness of the oil film 11 to be measured is measured. The ultrasonic transducer 1 is both an ultrasonic wave emitter and an ultrasonic wave receiver. It transmits the ultrasonic wave to the medium such as the oil film 11 to be measured, and collects the ultrasonic wave reflected back by the medium such as the oil film 11 to be measured. The ultrasonic wave reflected to the ultrasonic transducer 1 will cause the chip assembly inside the ultrasonic wave to generate mechanical vibration. The mechanical vibration caused thereby forms an electrical signal through the piezoelectric effect and is transmitted to the ultrasonic wave signal receiving module of the ultrasonic wave signal generation and reception module 10. The electrical signal received by the ultrasonic wave signal receiving module can be used for subsequent data processing and related calculations.

During operation, the horizontal moving platform 5 drives the ultrasonic transducer 1 to a horizontal position that meets the measurement requirements, rotates the driving handle 4-2 of the vertical moving platform 4, drives the ultrasonic transducer 1 to adjust the height direction, and gradually immerses the ultrasonic transducer 1 in the water 12 in the water tank 9 (the water 12 is used as a coupling agent, and its function is to exclude the air between the probe of the driving ultrasonic transducer 1 and the object to be measured, so that the ultrasonic wave can effectively penetrate the oil film 11 to achieve the detection purpose), and performs necessary pitch and yaw angle adjustments on the two-dimensional angle adjustment platform 3 to adjust the spatial posture of the ultrasonic transducer 1, so as to obtain a higher ultrasonic reflectivity.

The ultrasonic transducer 1 is both an ultrasonic wave emitting device and an ultrasonic wave receiving device. The ultrasonic signal generating and receiving module 10 releases an excitation signal to excite the ultrasonic transducer 1 to generate ultrasonic waves, and transmits the ultrasonic waves to the oil film 11 (i.e., the object to be detected); at the same time, the ultrasonic transducer 1 collects the ultrasonic waves reflected back from the oil film 11, and transmits them to the ultrasonic signal generating and receiving module 10 and performs corresponding data processing, thereby obtaining the measurement result of the oil film thickness.

As shown in Fig. 1, Fig. 4 and Fig. 5, during the measurement of the oil film thickness, the head of the ultrasonic transducer 1 is immersed in water 12, so that the ultrasonic wave propagates along the four media shown in Fig. 1 (water 12, upper slide 8-2, oil film 11, lower slide 8-4 from top to bottom), and a contact interface is formed between the two adjacent contacting media. Three interfaces are formed between the above four media, interface 13 corresponds to the contact interface between water 12 and upper slide 8-2, interface 2 14 corresponds to the contact interface between upper slide 8-2 and oil film 11, and interface 3 15 corresponds to the contact interface between oil film 11 and lower slide 8-4. Water is used as a coupling agent, and its function is to exclude the air between the ultrasonic transducer 1 and the object to be measured (oil film 11), so that the ultrasonic wave can effectively penetrate the oil film 11 to achieve the purpose of detection.

The reflection and projection principle of ultrasonic waves at the interface is shown in FIG2. When ultrasonic wave _T0 is incident vertically on interface 1 13, a part of the ultrasonic wave passes through interface 1 13 and enters the upper slide plate 8-2, becoming the transmission wave _T1 ; the other part of the ultrasonic wave is reflected back by interface 1 13, becoming the reflection wave _R1 . After the transmission wave _T1 enters the upper slide plate 8-2, it continues to propagate forward. When the transmission wave _T1 reaches interface 2 14, it is reflected and transmitted again. Its reflection wave _R2 propagates in the upper slide plate 8-2 and propagates into the water 12 via interface 1 13. Its transmission wave _T2 enters the oil film 11 medium and propagates. After the transmission wave _T2 enters the oil film 11, it continues to propagate forward. When the transmission wave _T2 reaches interface 3 15, it is reflected and transmitted again. Its reflection wave _R3 propagates into the water 12 via the oil film 11, interface 2 14, upper slide plate 8-2, and interface 1 13.

The ultrasonic transducer 1 can receive the reflected waves R ₁ , R ₂ , and R ₃ passing through the interface 13 and transmit them to the ultrasonic signal generating and receiving module 10 for data processing. According to the relevant information of the reflected waves R ₂ and R ₃ , the oil film thickness is calculated by the formula It is calculated that h is the oil film thickness, c is the propagation speed of ultrasound in the oil film 11, m is the resonance order of the oil film 11, and _fm is the m-th order resonance frequency of the oil film 11.

Claims (5)

1. A method for calibrating hydrostatic guideway oil film stiffness based on ultrasonic technology, characterized in that: said method is realized by utilizing a kind of ultrasonic detection device for measuring the thickness of hydrostatic guideway oil film, said one for The ultrasonic testing device for measuring the oil film thickness of the hydrostatic guide rail includes a gantry (6), a horizontal moving platform (5), a vertical moving platform (4), a two-dimensional angle adjustment table (3), an ultrasonic transducer (1) and Ultrasonic signal generating and receiving module (10); The ultrasonic transducer (1) is fixedly connected to the two-dimensional angle adjustment platform (3) through the transducer bracket (2), and the two-dimensional angle adjustment platform (3) is fixedly installed on the vertical mobile platform (4) , the vertical mobile platform (4) is fixedly installed on the horizontal mobile platform (5), the horizontal mobile platform (5) is fixed on the horizontal beam of the gantry (6), and the gantry (6) is fixed on On the ultra-precision machining machine bed (7), the ultrasonic signal generating and receiving module (10) is fixed on the ultra-precision machining machine bed (7); the ultrasonic signal generating and receiving module (10) is connected with the ultrasonic transducer ( 1) Signal transmission is carried out through the two-way connection of cables; the two-dimensional angle adjustment platform (3) is formed by stacking a pitching platform and a yaw platform, and the pitching platform is located at the lower part of the yaw platform, and the pitch platform and the yaw platform The structure is the same, the pitching platform includes a pitching adjustment knob (3-3), a pitching platform locking screw (3-4), a pitching platform fixing part (3-5), and a pitching platform locking piece (3-5-1) , the pitching table rotating part (3-6) and the pitching table worm (3-9); the yaw table includes a yaw adjustment knob (3-1), a yaw table locking screw (3-2), a yaw table Table fixed part (3-7), yaw table locking piece (3-7-1), yaw table rotating part (3-8) and yaw table worm; The yaw table rotating part (3-8), the yaw table fixing part (3-7), the pitching table rotating part (3-6) and the pitching table fixing part (3-5) are stacked sequentially from top to bottom Setting, the fixed part (3-7) of the tilting platform is detachably and fixedly connected with the rotating part (3-6) of the pitching platform, and the upper surface of the fixed part (3-5) of the pitching platform is provided with an inner wall through the front and rear side walls. Groove 1, the middle part of the left and right side walls of the inner groove 1 is provided with an upwardly protruding bump 1, and the two top angles of the upper surface of the bump 1 are respectively a right angle and an inverted V-shaped angle, located in the inner concave The protrusions on the left and right side walls of the groove one are arranged symmetrically with respect to the center of the pitching platform fixed part (3-5), and the lower surface of the pitching platform rotating part (3-6) is provided with an arc-shaped protrusion one, and the pitching platform rotates The left and right sides of the component (3-6) are respectively provided with a guide groove 1 matched with the bump 1, and the pitch adjustment knob (3-3) is fixedly connected with one end of the pitching platform worm (3-9), and the pitching platform The left and right side walls of the fixed part (3-5) are coaxially provided with two through holes one, the two ends of the pitching platform worm (3-9) are rotationally connected with the two through holes one, and the pitching platform rotating part (3-9) 6) The arc-shaped protrusions are made into a worm gear structure meshed with the worm (3-9) of the pitching platform, and threaded holes are provided on the front side wall or the rear side wall of the rotating part (3-6) of the pitching platform. The pitching platform locking piece (3-5-1) is arranged at the front side wall or the rear sidewall of the pitching platform rotating part (3-6) and the pitching platform fixing part (3-5), and the pitching platform locking piece (3-5-1) is provided with an arc-shaped long groove 1, and the pitching platform locking screw (3-4) penetrates into the arc-shaped long groove 1 and is threadedly connected with the threaded hole 1; The upper surface of the fixed part (3-7) of the tilt table is provided with an inner groove 2 passing through the left and right side walls, and the middle part of the front and rear side walls of the inner groove 2 is provided with an upwardly protruding bump 2. The two vertex angles on the upper surface of the projection two are right angles and inverted V-shaped angles respectively, and the two projections located on the front and rear side walls of the inner groove two are arranged symmetrically with respect to the center of the deflection table fixing part (3-7). The lower surface of the yaw table rotating part (3-8) is provided with arc-shaped protrusions 2, and the front and rear sides of the yaw table rotating part (3-8) are respectively provided with guide grooves 2 matched with the bulges 2, The yaw adjustment knob (3-1) is fixedly connected to one end of the yaw table worm, and the front and rear side walls of the yaw table fixing part (3-7) are coaxially provided with two through holes 2, and the two yaw table worms are The end is connected with the two through holes 2, and the arc-shaped protrusion 2 of the yaw table rotating part (3-8) is made into a worm wheel structure meshed with the yaw table worm, and the yaw table rotating part (3-8) 8) There is threaded hole 2 on the left side wall or the right side wall, and the yaw table locking piece (3-7-1) is arranged on the yaw table rotating part (3-8) and the yaw table fixed part On the left or right side wall of (3-7), the locking plate (3-7-1) of the tilting platform is provided with a circular arc-shaped long groove 2, and the locking screw of the tilting platform (3-2 ) penetrates into the arc-shaped long slot 2 and is threadedly connected with the threaded hole 2; the ultrasonic transducer (1) is fixed with the yaw table rotating part (3-8) by the transducer bracket (2) connection; the method steps are as follows: Step 1: driving the hydrostatic guide rail (8) to the measurement position; Step 2: Stick the water tank (9) to the upper end of the hydrostatic guide rail (8) directly above the oil film (11) to be tested, and add tap water or purified water to the water tank (9); Step 3: Drive the horizontal mobile platform (5) to adjust the lateral position of the ultrasonic transducer (1), so that the ultrasonic transducer (1) is directly above the water tank (9); drive the vertical mobile platform (4) to adjust the ultrasonic transducer (1) The height position of the transducer (1) is such that the head of the ultrasonic transducer (1) is gradually immersed in the water in the tank (9), ensuring that the head of the ultrasonic transducer (1) is in contact with the hydrostatic guide rail (8 ) keeps a distance of 2-10mm on the upper surface of the upper slide plate (8-2); Step 4: Adjust the pitch and yaw angles of the two-dimensional angle adjustment table (3), so that the axis of the ultrasonic transducer (1) is perpendicular to the surface of the upper slide (8-2); Step 5: start the ultrasonic signal generation and receiving module (10), the ultrasonic signal generation and receiving module (10) comprises an ultrasonic signal generation module and an ultrasonic signal receiving module, and ultrasonic parameters are set in the ultrasonic signal generation module, i.e. the intensity and frequency of the ultrasonic wave , the formula for calculating the oil film thickness is as follows; Where: h is the oil film thickness; c is the propagation velocity of ultrasonic wave in oil film (11); m is the resonance order of the oil film (11); f _m is the m-order resonance frequency of the oil film (11); Step 6: Apply a load on the upper slide plate (8-2) of the hydrostatic guide rail (8) through the cylinder, the load is increased by 500N, and gradually loaded to 2500N, and the thickness of the oil film after each load is measured by the ultrasonic detection device ;In this step, every time the load value is changed, it is necessary to return to step 5 to re-measure the oil film thickness to determine the corresponding oil film thickness when the load is applied. After the oil film thickness under all loads has been measured, Execute step seven; Step 7: Record each load value and its corresponding oil film thickness value in the test data recording table; Step 8: As the load acting on the oil film (11) increases, the oil film thickness will gradually become thinner, and the ratio of each load change to the oil film thickness change is calculated, that is, the oil film stiffness; Wherein: k is oil film stiffness, unit is N/μm, represents the load value that oil film (11) unit deformation can bear; ΔF is the load variation, the load is increased by 500N, and gradually loaded to 2500N; Δh is the variation of oil film thickness after each loading; Since the load change ΔF is a fixed value, and the oil film thickness change Δh after each loading is constantly changing, there is a difference in the oil film stiffness values in any two adjacent measurement points, and the oil film stiffness value cannot be obtained accurately. For this reason, the load value is taken as the Y coordinate and the oil film thickness value is taken as the X coordinate, and the linear least square method is used to perform linear fitting on the load value and the oil film thickness value, and the absolute value of the slope of the fitted straight line obtained is the oil film stiffness. 2. The method for calibrating the oil film stiffness of a hydrostatic guide rail based on ultrasonic technology according to claim 1, characterized in that: the arc radius of the arc-shaped long groove 1 and the rotation of the pitching platform rotating part (3-6) The radius is the same, and the radius of the arc of the arc-shaped long groove 2 is the same as the radius of rotation of the rotating part (3-8) of the yaw table. 3. the method for calibrating the oil film stiffness of hydrostatic guide rail based on ultrasonic technology according to claim 1, is characterized in that: described vertical mobile platform (4) comprises driving handle (4-2), vertical mobile screw ( 4-3), gear protection cover (4-4), driving gear (4-5), driven gear (4-6), vertical moving stage (4-11), vertical base (4- 12), two bearings (4-9), two vertically moving guide rail slides (4-7), four vertically moving sliders (4-8) and two support plates (4-10); The driving handle (4-2) is connected with the driving gear (4-5) through a rotating shaft to realize synchronous movement, and the driving gear (4-5) is meshed with the driven gear (4-6) and is installed together in the gear protection Inside the cover (4-4), the driven gear (4-6) is fixedly mounted on the vertically moving lead screw (4-3), and the two support plates (4-10) are oppositely arranged and fixed on on the vertical base (4-12), and one of the support plates (4-10) is fixedly connected to one end of the gear guard (4-4), and each of the two ends of the vertically moving lead screw (4-3) is installed There is a bearing (4-9), and the two bearings (4-9) are arranged in two shaft holes coaxially provided on the two support plates (4-10), and the vertically moving screw (4-10) 3) Two vertically moving guide rail slides (4-7) are arranged in parallel on both sides, and the two vertically moving guide rail slideways (4-7) are fixed on the vertical base (4-12), And the two ends of the two vertically moving guide rail slideways (4-7) are fixedly connected with the two support plates (4-10), and the vertically moving leading screw (4-3) is screwed and connected with a vertically moving leading screw nut, and the vertically moving lead screw nut is fixed on the back of the vertically moving stage (4-11), and the vertically moving stage (4-11) moves through four vertically moving slide blocks (4-8 ) is slidingly connected with two vertically moving guide rail slideways (4-7). 4. The method for calibrating the oil film stiffness of a hydrostatic guide rail based on ultrasonic technology according to claim 3, characterized in that: the vertical mobile platform (4) also includes a locking device (4-1); the locking The device (4-1) includes a fixed sleeve (4-1-1) with an opening, a handle (4-1-2) and a fastening screw; one end of the handle (4-1-2) is connected with the fastening screw As a whole, the two open ends of the fixed sleeve (4-1-1) are coaxially provided with two screw holes, the fixed sleeve (4-1-1) is set on the rotating shaft, and the fastening screw and Two screw holes threaded connection. 5. The method for calibrating the oil film stiffness of a hydrostatic guide rail based on ultrasonic technology according to claim 1, characterized in that: the horizontal moving platform (5) includes a servo motor (5-5), a shaft coupling (5- 4), horizontal moving stage (5-6), horizontal moving screw (5-1), base one (5-9), two screw bearings (5-3), two horizontal moving guide rails Slideway (5-7) and four leading screws horizontally move slide block (5-8); The base one (5-9) is fixedly connected to the front surface of the horizontal beam of the gantry (6), and the servo motor (5-5), two screw bearing blocks (5-3) and two horizontally moving The guide rail slideways (5-7) are all fixed on the base one (5-9), and the servo motor (5-5) is connected with one end of the horizontally moving lead screw (5-1) through a coupling (5-4) , the two ends of the horizontally moving screw (5-1) are supported by two screw bearing housings (5-3), the horizontally moving screw (5-1) and two horizontally moving guide rail slideways (5- 7) They are set parallel to the horizontal beams of the gantry (6), and the two horizontally moving guide rail slides (5-7) are located on both sides of the horizontally moving screw (5-1), and the horizontally moving screw (5-1) ) is screwed and connected with a horizontally moving lead screw nut, which is fixedly connected to the back of the horizontally moving stage (5-6), and the horizontally moving stage (5-6) is connected by four wires The horizontal movement slide block (5-8) of the bar is slidably connected with two horizontal movement guide rail slideways (5-7).